1. Field of the Invention
A battery assembly for attachment to an exterior surface of a photographic camera.
2. Description of the Prior Art
Generally, cameras of today include a battery which provides a source of energy for running various components of the camera which relate to the processing of a film unit, i.e., the steps one takes to produce an image either latent or visible, in the film unit. These components may take the form of an exposure control circuit, a flash firing circuit, motors for driving film advancing apparatus, shutter cocking and release, and in the case of cameras of the self-developing or instant type apparatus for driving at least one of a pair of rollers in order to spread a processing fluid across a photosensitive element of the film unit to initiate development of a visible image in the film unit. In most instances, the battery is located within the camera and if it must be replaced because of some defect within the battery itself such as an open or shorted internal circuit or because its energy level has dropped below that required to operate any of the components of the camera, then the camera must be opened in order to replace the battery. Sometimes, a problem arises when there is a supply of film in the camera's film chamber at the time that the battery fails, i.e., the lighttightness of the exposure chamber is violated thereby possibly resulting in premature exposure of part or all of the film supply contained therein.
The above problem of a battery failing at an inopportune time is minimized to a degree by periodically replacing the battery every time a new film cassette containing a new battery is inserted into the camera, as taught by U.S. Pat. Nos. 3,750,551 and 2,213,768. However, since the battery is now within the cassette, failure of the battery will necessarily result in the loss of the unexposed film supply within the cassette.
It has also been proposed to provide a camera with a separate compartment for receiving batteries, the compartment being configured so as to prevent incorrect insertion of a battery into the compartment. While this teaching may solve the problem of violating the lighttightness during replacement of the batteries of the exposure chamber, the solution does not lend itself to minimizing the size of the camera; nor does it provide a solution for those cameras wherein the battery is located within the film cassette. Also, cameras having an exteriorly mounted source of energy have been described in the prior art. For example U.S. Pat. No. 3,853,396 discloses a camera having an internal battery which is coupled to a motor, and an auxiliary unit including a battery which is adapted to be attached to the camera such that the two batteries are in series. Also see German Offenlegunzsschrift No. 2330766 (Offenlezunzstag: 9-1-75) wherein is shown a camera having a recess in an exterior surface for receiving a generally flat battery. However, the motors of many cameras would be burned out if their source of energy were connected in series with another source of energy as taught in the U.S. patent while the latter described German publication fails to correct the aforementioned problem concerning film cassettes having a defective battery therein. Further, as regards the last mentioned disclosure, there does not appear to be any teaching therein of configuring the battery and recess in such a way that proper insertion of the battery into the recess will be guaranteed.